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5fd54ace | 1 | // SPDX-License-Identifier: GPL-2.0 |
0062f6e5 SAS |
2 | #include <linux/kernel.h> |
3 | #include <linux/slab.h> | |
4 | #include <linux/module.h> | |
5 | #include <linux/err.h> | |
6 | ||
7 | #include <linux/usb/composite.h> | |
8 | ||
9 | static LIST_HEAD(func_list); | |
10 | static DEFINE_MUTEX(func_lock); | |
11 | ||
12 | static struct usb_function_instance *try_get_usb_function_instance(const char *name) | |
13 | { | |
14 | struct usb_function_driver *fd; | |
15 | struct usb_function_instance *fi; | |
16 | ||
17 | fi = ERR_PTR(-ENOENT); | |
18 | mutex_lock(&func_lock); | |
19 | list_for_each_entry(fd, &func_list, list) { | |
20 | ||
21 | if (strcmp(name, fd->name)) | |
22 | continue; | |
23 | ||
24 | if (!try_module_get(fd->mod)) { | |
25 | fi = ERR_PTR(-EBUSY); | |
26 | break; | |
27 | } | |
28 | fi = fd->alloc_inst(); | |
29 | if (IS_ERR(fi)) | |
30 | module_put(fd->mod); | |
31 | else | |
32 | fi->fd = fd; | |
33 | break; | |
34 | } | |
35 | mutex_unlock(&func_lock); | |
36 | return fi; | |
37 | } | |
38 | ||
39 | struct usb_function_instance *usb_get_function_instance(const char *name) | |
40 | { | |
41 | struct usb_function_instance *fi; | |
42 | int ret; | |
43 | ||
44 | fi = try_get_usb_function_instance(name); | |
45 | if (!IS_ERR(fi)) | |
46 | return fi; | |
47 | ret = PTR_ERR(fi); | |
48 | if (ret != -ENOENT) | |
49 | return fi; | |
50 | ret = request_module("usbfunc:%s", name); | |
51 | if (ret < 0) | |
52 | return ERR_PTR(ret); | |
53 | return try_get_usb_function_instance(name); | |
54 | } | |
55 | EXPORT_SYMBOL_GPL(usb_get_function_instance); | |
56 | ||
57 | struct usb_function *usb_get_function(struct usb_function_instance *fi) | |
58 | { | |
59 | struct usb_function *f; | |
60 | ||
61 | f = fi->fd->alloc_func(fi); | |
62 | if (IS_ERR(f)) | |
63 | return f; | |
64 | f->fi = fi; | |
65 | return f; | |
66 | } | |
67 | EXPORT_SYMBOL_GPL(usb_get_function); | |
68 | ||
69 | void usb_put_function_instance(struct usb_function_instance *fi) | |
70 | { | |
71 | struct module *mod; | |
72 | ||
73 | if (!fi) | |
74 | return; | |
75 | ||
76 | mod = fi->fd->mod; | |
77 | fi->free_func_inst(fi); | |
78 | module_put(mod); | |
79 | } | |
80 | EXPORT_SYMBOL_GPL(usb_put_function_instance); | |
81 | ||
82 | void usb_put_function(struct usb_function *f) | |
83 | { | |
84 | if (!f) | |
85 | return; | |
86 | ||
87 | f->free_func(f); | |
88 | } | |
89 | EXPORT_SYMBOL_GPL(usb_put_function); | |
90 | ||
91 | int usb_function_register(struct usb_function_driver *newf) | |
92 | { | |
93 | struct usb_function_driver *fd; | |
94 | int ret; | |
95 | ||
96 | ret = -EEXIST; | |
97 | ||
98 | mutex_lock(&func_lock); | |
99 | list_for_each_entry(fd, &func_list, list) { | |
100 | if (!strcmp(fd->name, newf->name)) | |
101 | goto out; | |
102 | } | |
103 | ret = 0; | |
104 | list_add_tail(&newf->list, &func_list); | |
105 | out: | |
106 | mutex_unlock(&func_lock); | |
107 | return ret; | |
108 | } | |
109 | EXPORT_SYMBOL_GPL(usb_function_register); | |
110 | ||
111 | void usb_function_unregister(struct usb_function_driver *fd) | |
112 | { | |
113 | mutex_lock(&func_lock); | |
114 | list_del(&fd->list); | |
115 | mutex_unlock(&func_lock); | |
116 | } | |
117 | EXPORT_SYMBOL_GPL(usb_function_unregister); |